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Midwest Residents Startled By Frost Quakes

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SOUTHFIELD (WWJ) – First, it was the “polar vortex” — that persistent upper atmosphere weather phenomenon that’s had us all locked in a deep freeze. Now, there’s a new phrase to add to your growing Winter weather lexicon… “frost quakes!”

The extreme cold temperatures this Winter have led to something known as “frost quakes,” creating loud cracking noises from underground that some residents have confused with gunshots.

“It is very much like a gunshot, maybe a gunshot from some distance,” says Kent State University geology professor Thomas Schmidlin, who says there have been reports of frost quakes across Michigan, Ohio and several other states.

“They are calling police departments and the police departments don’t know what to say, I think, in most cases. So it’s one of the quirky things about this cold winter weather we’re having this year,” says Schmidlin.

Frost quakes are actually the result of water a few feet underground rapidly freezing and expanding due to the extreme cold, resulting in an audible shockwave.

“Well, it’s really different from a geological earthquake, which is usually very deep in the earth and involves a fairly large shift of rock along the existing fault line. These, on the other hand, are due to the rapidly freezing shallow ground, probably just a foot or two down below the surface. And the water is freezing and expanding and that sometimes is reported as a very loud noise,” says Schmidlin.

Schmidlin says the phenomena, which he describes as “rare”, has occurred with more frequency this Winter, startling residents.

“These arctic fronts we’ve been getting, the temperature falls 20, 30, 40 degrees in a short time and that seems to be the time that people begin to hear these frost quakes,” he says.

But Schmidlin says outside of being startled by the noise, “frost quakes” are, essentially, harmless.